1. The Field of the Invention
The field of the invention relates to interfacing, analog and digital devices with a digital network system such as an Integrated Services Digital Network (ISDN) system. Additionally, the invention also relates to concurrently interfacing analog devices such as telephones, faxes, modems and computers to compatibly interface with an ISDN system. More particularly, the invention relates to providing an integrated, portable module for interfacing both analog and digital devices with an ISDN system.
2. Present State of the Art
Through recent decades, the majority of data transmitted between two locations utilized analog transmission devices such as analog telephones or analog modems. Analog networks facilitated interconnection of analog devices and provided a conduit for analog information exchange therebetween. As analog networks became congested and inadequate for facilitating the transfer of significant amounts of analog information, digital systems including high bandwidth systems were conceived. One such popular modern system includes the ISDN system wherein information is transferred and maintained in digital format. Furthermore, higher bandwidth encoding and modulation techniques facilitate the exchange of yet significant amounts of data between users.
As ISDN systems are becoming more ubiquitous, users are desiring access to larger reservoirs of digital data. To satisfactorily facilitate the exchange of significant amounts of digital data, users and network providers are migrating to higher bandwidth technology such as ISDN. Since the ISDN system accommodates the exchange of digital data only, all analog information must be digitized before transmission.
Additionally, users transitioning from an analog system to a digital system prefer continued use of existing analog devices as opposed to obsoleting such devices already procured. To facilitate the reuse of analog devices in a digital system, adapters have been developed to interface existing analog devices with the ISDN system. Referring to FIG. 1, an analog telephone 12 may independently operate in an analog telephone system, however, in a digital network, a terminal adapter 14 must transform an analog telephone signal from analog telephone 12 to a digitized and formatted digital data signal compatible with the digital standards of an ISDN system 10. Likewise, other analog devices such as a fax/modem 16 interact using analog signals and therefore must also utilize a terminal adapter 18 to facilitate conversion from an analog signal to a digital signal compatible with ISDN system 10. Furthermore, traditional digital devices such as a computer 20 employing an analog modem 22 for generation of interfacing analog signals must also utilize a terminal adapter 24 to convert the analog signals generated by analog modem 22 into a digitized format compatible with ISDN system 10.
Additionally, in an arrangement wherein a plurality of devices are to be employed, a network termination adapter (NT-1) 26 converts the 2-wire ISDN line from the telephone company, called the U interface, into an 8-wire S/T interface. An NT-1 26 may be employed when a user desires connectivity of multiple devices to one ISDN system. Therefore, referring to FIG. 1, to facilitate coupling analog phone 12, fax/modem 16 and computer 20 to ISDN system 10, three terminal adapters (14, 18 and 24), and an NT-1 26 are required to accommodate interfacing an analog phone, a fax/modem and a computer to an ISDN system.
Furthermore, modern applications of computers such as notebook computers dictate a portable or mobile environment wherein a user transports, carriers or otherwise has available to them portable office hardware such as a computer, a telephone and a fax. Such an operational environment renders the use of multiple terminal adapters and an NT-1 impractical and burdensome.
Thus, what is needed is a system and method for integrating a plurality of interface components into a portable module capable of practical transportation by a user with a computer and an analog telephone. Also, what is needed is a system and method for interfacing an analog telephone and a computer into an ISDN system wherein the direct interface with the ISDN system may take the form of either a U-interface or an S/T-interface.